Is heme iron intake associated with risk of coronary heart disease? A meta-analysis of prospective studies
Heme iron may contribute to the development of atherosclerosis by catalyzing production of hydroxyl-free radicals and promoting low-density lipoprotein oxidation. However, epidemiologic findings regarding the association between heme iron intake and risk of coronary heart disease (CHD) are inconsistent. We aimed to investigate the association by carrying out a meta-analysis of prospective studies.
Relevant studies were identified by using PubMed and EMBASE databases between January 1966 and April 2013 and also by manually reviewing the reference lists of retrieved publications. Summary relative risks (RRs) with corresponding 95 % confidence intervals (CIs) were computed using a random-effects model.
Six prospective studies, which contained a total of 131,553 participants and 2,459 CHD cases, met the inclusion criteria. Combined results indicated that participants with higher heme iron intake had a 31 % increased risk of CHD, compared with those with lower intake (RR = 1.31, 95 % CI 1.04–1.67), with significant heterogeneity (Pheterogeneity = 0.05, I2 = 55.0 %). Excluding the only study from Japan (limiting to Western studies) yielded a RR of 1.46 (95 % CI 1.21–1.76), with no study heterogeneity (Pheterogeneity = 0.44, I2 = 0.0 %). The dose–response RR of CHD for an increase in heme iron intake of 1 mg/day was 1.27 (95 % CI 1.10–1.47), with low heterogeneity (Pheterogeneity = 0.25, I2 = 25.8 %). We observed no significant publication bias.
This meta-analysis suggests that heme iron intake was associated with an increased risk of CHD.
KeywordsHeme iron Prospective studies Coronary heart disease Meta-analysis
- 3.Gupta R, Rastogi S, Nagar R, Kastia S, Kaul V (2000) Dietary and serum iron, body iron stores and coronary heart disease. J Assoc Physicians India 48:489–492Google Scholar
- 5.Tavani A, Gallus S, Bosetti C, Parpinel M, Negri E, La Vecchia C (2006) Dietary iron intake and risk of non-fatal acute myocardial infarction. Public Health Nutr 9:480–484Google Scholar
- 12.Cook JD (1990) Adaptation in iron metabolism. Am J Clin Nutr 51:301–308Google Scholar
- 15.de Oliveira Otto MC, Alonso A, Lee DH, Delclos GL, Bertoni AG, Jiang R, Lima JA, Symanski E, Jacobs DR Jr, Nettleton JA (2012) Dietary intakes of zinc and heme iron from red meat, but not from other sources, are associated with greater risk of metabolic syndrome and cardiovascular disease. J Nutr 142:526–533CrossRefGoogle Scholar
- 16.Lee DH, Folsom AR, Jacobs DR Jr (2005) Iron, zinc, and alcohol consumption and mortality from cardiovascular diseases: the Iowa Women’s Health Study. Am J Clin Nutr 81:787–791Google Scholar
- 20.Greenland S, Longnecker MP (1992) Methods for trend estimation from summarized dose-response data, with applications to meta-analysis. Am J Epidemiol 135:1301–1309Google Scholar
- 21.Orsini N, Bellocco R, Greenland S (2006) Generalized least squares for trend estimation of summarized dose-response data. Stata J 6:40–57Google Scholar
- 31.Higgins JP, Green S, Collaboration C (2008) Cochrane handbook for systematic reviews of interventions. Wiley Online Library, United StatesGoogle Scholar